Development and Characterization of new Alloys of the Ti-25Ta-Zr system for Biomedical Applications

Abstract

Due to excellent biocompatibility and corrosion resistance of titanium alloys, their applications in orthopedic and dental implants have gained strength since 1970. However the Young's modulus of these alloys is still about 2 to 4 times higher than the human bone. The most widely used titanium alloy for biomedical applications is Ti-6Al-4V, however, previous studies showed that vanadium cause allergic reactions in human tissue and aluminum has been associated with neurological disorders. So, to circumvent this problem, new titanium alloys without the presence of these elements are being developed, with the addition of different elements, usually ²-stabilizers, which can change its microstructure and mechanical properties being able to make titanium and its alloys, most promising for use as biomaterial. The most promising are the alloys with niobium, zirconium, molybdenum and tantalum as alloying elements, added to the titanium. The main objective of this project is the development and characterization of Ti-25Ta-Zr system alloys, containing various levels of zirconium, for biomedical applications. Ti-25Ta (wt%) was chosen as the base alloy, because this is the alloy with best mechanical properties and biocompatible, besides owning the coexistence phase ±' (which has hexagonal compact structure) and ±'' phase (which has orthorhombic structure). In titanium alloys, both the substitutional element as thermo-mechanical treatments has strong influence on structure and properties of alloys. Thus, this project also aims to analyze the effect of substitutional element, zirconium, in structure, microstructure, some selected mechanical properties (hardness and modulus of elasticity), in addition to the biocompatibility of prepared alloys. In parallel, also aims to investigate the influence of thermal treatments and mechanical processing, in the structure, microstructure and selected mechanical properties of the alloys.